Nonlinear transmission matrix of random optical media

Random media with tailored optical properties are attracting burgeoning interest for applications in imaging, biophysics, energy, nanomedicine, spectroscopy, cryptography and telecommunications.
A key paradigm for devices based on this class of materials is the transmission matrix, the tensorial link between the input and the output signals, that describes in full their optical behavior. The transmission matrix has specific statistical properties, as the existence of lossless channels, that can be used to transmit information, and are determined by the disorder distribution. In nonlinear materials, these channels may be modulated and the transmission matrix tuned accordingly. Here we
report the direct measurement of the nonlinear transmission matrix of complex materials, exploiting the strong optothermal nonlinearity of scattering Silica Aerogel (SA). We show that the dephasing effects due to nonlinearity are both controllable and reversible, opening the road to applications based on the nonlinear response of random media.

A. Fleming, C. Conti, A. Di Falco, arXiv:1809.07077

Accelerated electrons go farther if out-of-equilibrium

ArXiv:1808.03669

We explore the nonlinear response of plasmonic materials driven by ultrashort pulses of electromagnetic radiation with temporal duration of few femtoseconds and high peak intensity. By developing the Fokker-Planck-Landau theory of electron collisions, we solve analytically the collisional integral and derive a novel set of hydrodynamical equations accounting for plasma dynamics at ultrashort time scales. While in the limit of small light intensities we recover the well established Drude model of plasmas, in the high intensity limit we observe nonlinear quenching of collision-induced damping leading to absorption saturation. Our results provide a general background to understand electron dynamics in plasmonic materials with promising photonic applications in the manipulation of plasma waves with reduced absorption at the femtosecond time scale.

Andrea Marini, Alessandro Ciattoni, and Claudio Conti, Collision quenching in the ultrafast dynamics of plasmonic materials in ArXiv:1808.03669

Nonlinear Optics 2019 at Hawaii launched !!!

The NLO 2019 OSA workshop has been launched. This is the periodical world-famous event on the last developments of nonlinear optics.

The NLO 2019 edition will be open to new directions as quantum nonlinear optics, machine learning, novel soft- and bio-materials,  nanomedicine and imaging applications. 

Stay tuned and do not miss the opportunity to visit Hawaii and enjoy an exciting scientific and natural environment.

The Bathynomus propinquus

Testing the new Gutenberg editor of WordPress : the visit at the Harvard Museum of Natural History

One of the most surprising animals of the last century :  the Bathynomus propinquus

Why this nice fluffy has such big eyes if he leaves in the soil of the dark deep ocean?

I first read about the giant isopod in the wonderful book “In the Blink of an Eye” by Andrew Parker, a surprising tour in evolution and the Cambrian explosion , see the enlightened game of life.

Recently, I was able to visit the Harvard Museum of Natural Hystory, where you find the footprints of writers and scientists as Stephen Jay Could, and you can meet the fluffy puppy above.

With a primitive fish (the one smiling but without glasses) at the Harvard Museum

Read many books for many years ! (and visit the museums)

Planckian signatures in optical harmonic generation and supercontinuum

Many theories of quantum gravity, as string theory, loop quantum gravity, and doubly special relativity, predict the existence of a minimal length scale and outline the need to generalize the uncertainty principle. This generalized uncertainty principle relies on modified commutation relations that – if applied to the second quantization – imply an excess energy of the electromagnetic quanta with respect to ω. Here we show that this “dark energy of the photon” is amplified during nonlinear optical process. Therefore, if one accepts the minimal length scenario, one must expect to observe specific optical frequencies in optical harmonic generation by intense laser fields. Other processes as four-wave mixing and supercontinuum generation may also contain similar spectral features of quantum-gravity. Nonlinear optics may hence be helpful to falsify some of the most investigated approaches to the unification of quantum mechanics and general relativity.

C. Conti in arXiv:1805.11716